Name: コンクリートが乾かない (Concrete Does Not Dry Out)
Uploaded: 2021-01-14T10:20:03.000Z
Duration: 2 min 4 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

In a few hours, this sloppy wet concrete will harden into

関係詞節（制限と非制限）

a solid, which, after a few days will be strong enough to hold many tons of weight.

Pasta also starts in a moist amorphous state, hardens after a few hours, and it can also hold

But there’s an important difference between capellini and concrete – noodles dry out

(which you can tell because when you add water, they re-absorb it and become soft again),

while concrete sets (you can pour as much water on it as you want, and it won’t become

soggy - which is good because you don’t want buildings and bridges to get soggy when

The distinction is that when pasta is made, water simply evaporates out of the dough,

leaving behind a desiccated, starchy scaffolding with plenty of holes & gaps ready to re-absorb

water in the future and re-soften the dough.

When concrete sets, on the other hand, calcium oxide, silicon dioxide and other molecules

in the cement chemically combine with water molecules to create new compounds like calcium

silicate hydrate. These molecules grow into crystalline fibers that bond with each other

and literally cement together rock, sand, metal or whatever else you put into the mix.

So when concrete hardens, it’s not drying out, because water isn’t leaving it – water

is reacting with and becoming PART of the cement. In fact, concrete continues to set

for months and even years after it’s poured, increasing in strength over time and enabling

the construction of miraculously strong and durable structures, like the 2000 foot tall CN Tower in Toronto